The invention relates to the field of oil processing and the petrochemical industry, mainly to installations for the vacuum distillation of liquid products, crude oil for example. It and can be used particularly for the rectification of oil stock.
A vacuum system for crude oil rectification, which exploits a water steam ejector for producing a vacuum in a vacuum rectification column, is known (see U.S. Pat. No. 2,680,709, cl. 202-204, 1954).
Waste water with emulsified impurities of petroleum derivatives is formed as a result of operation of this system. Such waste water is environmentally dangerous and its purification from petroleum emulsions is a complex technical problem, requiring significant expenses.
The authors have chosen the pumping-ejector vacuum unit for distillation of liquids disclosed in RU patent No. 2048156 (M cl..sup.6 B 01 D 3/10, 1995) as the starting point for the present invention. This unit comprises
a vacuum rectification column with pipelines for feed of a stock product, for discharge of vapors and for export of a liquid fraction; PA1 a vacuum-producing device composed of a liquid-gas jet apparatus, a separator and a pump.
In operation of this system, evacuation of vapors from the rectification column is carried out by the liquid-gas jet apparatus. The liquid-gas jet apparatus uses the liquid fraction from the rectification column as an active medium. Use of such unit substantially reduces the environmental discharge of ecologically harmful refinery waste.
The main imperfection of this system is the low efficiency of the vacuum-producing device since there is no makeup of the motive liquid during operation and the motive liquid is saturated in a short time by impurities, which negatively affect performance of the liquid-gas jet apparatus.